What happens when you get 500 moons in Mario Odyssey?

Excuse me, could you please elaborate on what exactly occurs in the game Mario Odyssey when a player accumulates 500 moons? I'm curious to know if there's a specific milestone, unlockable content, or any other significant event that takes place upon reaching this milestone. It would be helpful if you could provide a concise yet informative overview of the consequences of obtaining 500 moons in Mario Odyssey.